Soy based protein shakes- any good?

 Hi,

I know we are supposed to use the whey based protein drinks, but I have lactose issues.  Does anyone know if the soy based protein is good, or is it to be avoided like the casein based stuff?

Typically, the whey based drinks that have whey protein isolate are 90% protein and lactose free.  (I just took a training class for work that got into the difference between whey proteins and whey protein isolates and casein protein.)  Nectars I know for sure are lactose free.  

I can't speak too intelligently about the soy based proteins, so nothing to add there.  Hopefully someone else can chime in.